As doctors continue to monitor Rep. Gabrielle Giffords's condition, previous cases of brain injury resulting from bullets and other assaults can help explain what happens to the nervous system during major injuries--and how those rare recoveries are possible

Bob Woodruff Perhaps the vast majority of brain injuries happen not from penetration, such as a gunshot wound, but are so-called closed-head injuries that occur when the brain is assaulted by outside force—whether that is from a car crash or a nearby explosion.

Common concussions, such as those often sustained in football, are minor closed-head injuries and can cause confusion, headaches and memory loss, most of which usually disappear with time (although repeated assaults of this magnitude can have a cumulative effect on cognitive functioning).

Major closed-head brain injury, such as that sustained by ABC reporter Bob Woodruff in Iraq when the convoy he was traveling in struck an improvised explosive device in 2006, can have lasting, if not fatal consequences. At this level of injury, "you start to see much more pronounced swelling" and the brain becomes less adept at moving protein and calcium, which are crucial to its chemical balance, Nuwer explains. After Woodruff's injury, doctors put him into a medically induced coma for 36 days. Woodruff returned to work a little more than a year after his injury, but even then he still occasionally had difficulty with words, according to ABC. WIKIMEDIA COMMONS

Columbine Survivor If a bullet does not pass all the way through the head at the time of the shooting, doctors will often try to remove it surgically to reduce the risk of infection. But if the projectile is lodged too deeply or in too sensitive a brain area, occasionally, it will be left in. "You don't actually have to take the metal out of the head," Nuwer says.

Patrick Ireland was shot once in the foot and twice on the left side of the head during the 1999 shootings at Columbine High School in Littleton, Colo. One of the bullets "penetrated his brain and traveled eight inches to the back of his skull," a 1999 news report noted. Although Ireland was still suffering from speech problems and partial paralysis on his right side in the months after the shooting, as of two years ago at the age of 27, he had only a slight limp. ISTOCKPHOTO/VLADIMIR1965

George Wallace Bullets do not have to enter the brain to do lasting neurological damage. In 1972 presidential hopeful and Alabama Governor George Wallace was shot several times with a .38-caliber gun at a distance of slightly less than half a meter. One of the bullets, which entered near his waist, was lodged in the spinal canal, the hole in the spinal column through which the nerve bundles pass.

"The very impact of the bullet probably bruised the delicate nerve tissue severely," according to an article written at the time. The severed nerves meant that "Wallace reported no feeling in his legs," the report noted; had the bullet landed higher up in the vertebral column, he likely would have lost more motor function. As it was, he needed a wheelchair to get around afterward but was able to return to work as governor. WIKIMEDIA COMMONS

Phineas Gage In one of the most famous examples of penetrating brain injury, an explosion sent a metal rod through railroad-worker Phineas Gage's head. The rod, protruding from his left cheekbone and the top of his skull, passed through the brain's frontal lobes, which are responsible for personality among other advanced functions.

Although Gage survived the traumatic injury and retained reasoning capabilities, the damage to his brain changed his personality. Once a tolerant overseer, after the injury he became "fitful, irreverent, indulging at times in the grossest profanity (which was not previously his custom)," his doctor J. M. Harlow wrote in a 1868 report in the Bulletin of the Massachusetts Medical Society. "His mind was radically changed—so decidedly that his friends and acquaintances said he was 'no longer Gage.'" WIKIMEDIA COMMONS

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James Brady A minority of people who suffer a gunshot wound to the head survive. A bullet that traveled through both brain hemispheres left President Ronald Reagan's press secretary James Brady partially disabled after a 1981 assassination attempt that also injured the president.

Having entered through the left forehead, the bullet traveled through part of Brady's corpus callosum and into his right frontal lobe, according to news reports at the time. The bullet "appeared to go through his motor area and the areas that control speech," Nuwer explains. Brady's speech and movement were so impaired that the injury "basically was a career ender for him." The surgeons at the time had early indications that the wound would likely have dire consequences. "Mr. Brady had no movement on his left side and his right side moved only in response to the deepest pain," a New York Times article noted at the time. WIKIMEDIA COMMONS

Robert F. Kennedy When presidential candidate Sen. Robert F. Kennedy (D–N.Y.) was shot with a .22-caliber revolver in 1968, one of the bullets tore through his torso, another traveled from his armpit through the back of his neck, and a third entered his head behind his right ear. This third bullet caused severe bleeding and swelling in the brain, putting pressure on the midbrain, which controls basic functions.

Even though doctors removed part of Kennedy's skull to relieve pressure, as they have done in the case of Rep. Giffords's case, brain swelling continued "so much so that the swelling became out of control and escaped the ability of the medical science at the time," says Marc Nuwer, critical care expert and neurologist at the University of California, Los Angeles, and member of the American Academy of Neurology. WIKIMEDIA COMMONS

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